51. She gave ________ directions about the way the rug should be cleaned.

　　A) explicit C) transient

　　B) brisk D) opaque

　　52. It took a lot of imagination to come up with such a(n) ________ plan.

　　A) inherent C) vigorous

　　B) ingenious D) exotic

　　53. A ________ official is one who is irresponsible in his work.

　　A) timid C) suspicious

　　B) tedious D) slack

　　54. Most mathematicians trust their ________ in solving problems and readily admit they would not be able to function without it.

　　A) conception C) intuition

　　B) perception D) cognition

　　55. He had an almost irresistible ________ to talk to the crowd when he entered Hyde Park.

　　A) impulse C) stimulation

　　B) instinct D) surge